ISO 639-1 ⇝

language code

(human language,
standard) A set of standard names and abbreviations maintained by ISO for identifying human languages, natural and invented, past and present. Each language has a list of English and French names and an ISO 639-2 three-letter code. Some also have an ISO 639-1 two-letter code.

The list even includes the Klingon language from the Star Trek science fiction series.